XJ128 and XJ128 Plus Printhead
XJ128 Guide to Operation
Xaar Document no: D031010302 Version A
Page 24
Figure 5.1 - Signal level definition
5.3 Signal descriptions
nSS1 and nSS2
Active low. Chip select lines for driver chip 1 and 2. A low level selects the corresponding 64-channel
segment as receiver of the MOSI data. This signals controls the MISO tri-state output signal.
VDD
Power supply for logic circuit. Should be set at +5.0V.
VPPL
Low current, low noise, high voltage power supply. Should be set to +35V.
VPPH
High current, high voltage power supply. Should be set to +35V.
GND, GNDL, GNDH
Grounds for voltage power supplies.
nFAULT
Active low error output signal that indicates a high printhead temperature. Will stay active until
temperature goes below the high temperature threshold level, set to 45-55
° Celsius. An extern
al
system responding to an nFAULT alarm should stop printing and wait for the print head to cool.
The nFAULT driver does not have hysteresis and will begin to switch at a temperature
between 45-50
° C due to noise induced int
o the circuit when the head is fired. Be
aware that while READY is high there is no noise induced and nFAULT will be stable.
Therefore nFAULT should only be sampled while READY is high.
nRESET
Active low, asynchronous reset of the driver chip sequence logic. nReset will not reset the contents
of the input data shift registers.
MOSI
Serial data input (Master Out Slave In). Print data is loaded through this line.
Input
VIH
VIL
Output
90%
10%
